Launching this assembly into the water is a tricky operation. In general, the streamer 14 and the light cable 16 are first of all launched into the water using an ancillary winch (not depicted). Once this initial launch has been performed, the towfish 13 is connected to the light cable 16 and the main cable 12 is in turn connected to the towfish 13. The connections provide mechanical and electrical connection of the various subassemblies. Once these connections have been made, the rest of the launch procedure can be performed by means of the winch 11 in order to arrive at the configuration depicted in FIG. 1. The assembly is recovered by reversing the launch operations.
This procedure exhibits a number of deficiencies.
Mechanical and electrical continuity between the cable 12 and the streamer 14 is achieved through the towfish. If the sonar is to be operated in passive mode, which means to say with no acoustic emission on the part of the towfish, then it is still necessary to launch the towfish 13. This is because it is actually impossible to connect the streamer 14 to the main cable 12, potentially by way of the light cable 16 without passing via the towfish 13.
The mechanical and electrical connections are made in a hostile environment with a risk of corrosion due to the marine environment and with the personnel doing the manipulation exposed for a lengthy period to the swell.
If certain handling elements break, for example the ancillary winch, there is a risk of losing the streamer 14, or even the towfish 13.
The invention seeks to alleviate all or some of the problems mentioned above by eliminating the need for an ancillary winch and by proposing a sonar system in which the mechanical connections are premade and in which the fitting of the towfish is optional.